The CBI infighting began when its chief Alok Verma objected to Rakesh Asthana's appointment last year.

New Delhi: A day after the Central Bureau of Investigation or CBI arrested an investigating officer and conducted searches at its own headquarters, the Delhi High Court will take up a plea challenging the arrest. The CBI has accused Special Director Rakesh Asthana, the agency's number 2, of corruption and filed a bribery case that led to the arrest of Deputy Superintendent of Police Devender Kumar, who worked with Mr Asthana in the money laundering case involving meat exporter Moin Qureishi. Here are 10 points on the developing story:

Devender Kumar was arrested on Monday over allegations of forgery in recording the statement of businessman Sathish Sana, who had alleged to have paid bribes to get relief in the case. Mr Kumar approached the court seeking bail and the hearing will take place after lunch today.

The officer was arrested amid an intensifying battle within the country's top investigating agency after its top two officers made corruption allegations against each other. Last week, the CBI filed a bribery case against Mr Asthana, who in retaliation wrote to the government listing several charges against his boss, the agency's director Alok Verma.

The CBI's First Information Report (FIR) against Rakesh Asthana is based on the claims of Sathish Sana, a Hyderabad-based businessman investigated in connection with meat exporter Moin Qureshi, who is accused of money-laundering.

Satish Sana has alleged that he was asked to pay a bribe of Rs 5 crore to Mr Asthana to be rid of the case. Manoj Prasad, an investment banker based in Dubai, was allegedly the middleman who asked him to pay the bribe. Manoj Prasad was arrested on October 16 when he was returning from Dubai to allegedly collect an installment of the agreed bribe amount.

The CBI claims to have analysed nine phone calls immediately after the arrest, which, it says, shows panic after Manoj Prasad's brother Somesh learnt of his arrest. The calls were allegedly exchanged between Mr Asthana and a senior officer of another intelligence agency, who wanted to confirm details of the arrest.

Somesh Prasad has also been charged by the CBI. Manoj and Somesh are the sons of a former officer of the Research and Analysis Wing (R&AW). The CBI says the role of R&AW officials is also being investigated.

Mr Asthana alleged that it was the CBI chief who took the bribe but framed him because he prevented Satish Sana from escaping the country. Earlier this month, Mr Asthana had accused the CBI chief of trying to frame him in the case of Gujarat-based company Sterling Biotech, which is being investigated for loan default.

Sathish Sana had, during an interrogation, "admitted" to bribing the CBI director, Mr Asthana said in his letter to the Cabinet Secretariat. The letter listed 10 instances of corruption, criminal misconduct, interference in the investigation of the sensitive cases. Days after this letter, the CBI put out a statement that Mr Asthana's role was being investigated in several cases.

The case took a political twist with Congress president Rahul Gandhi targeting Prime Minister Narendra Modi on the infighting and accusing him, again, of making the agency a weapon of political vendetta. "The PM's blue-eyed boy, Gujarat cadre officer, of Godra SIT fame, infiltrated as No. 2 into the CBI, has now been caught taking bribes. Under this PM, the CBI is a weapon of political vendetta. An institution in terminal decline that's at war with itself," Mr Gandhi tweeted.

The CBI infighting started last year when the director objected to the appointment of Mr Asthana, a Gujarat cadre officer, as he was under investigation in the Sterling Biotech case.